Cartridge contains high quality activated carbon that keeps water clean
Installs in seconds: rinse first and align cartridge bottom key slot for an accurate fit inside the Filter
Easy installation using the "FRONT" orientation tab
For optimal performance, change approximately every 4 weeks
Fits Aqueon QuietFlow Filter: LED PRO Size 20, 30, 50 and 75, Power Filter Size 20, 30, 50, 55/75, E Internal Size 40, Canister Filter Size 200, 300 and 400